Is it permissible for a woman to wear temporary hair extensions for her husband's adornment, given that her hair is very thin?

If the hair is sparse to the point of being considered a defect, the suitor must be informed to avoid deception. As for hair extensions using other hair, it is forbidden by Islamic law in all cases, whether the husband knows or not, because the Prophet, peace and blessings be upon him, said: "Allah has cursed the one who extends hair and the one who has it extended." The prohibition includes the one who extends a woman's hair (the waasilah) and the one who requests it (the mustawsilah). Therefore, if a woman's hair falls out, she is not permitted to extend it; rather, she should seek medical treatment.